Anti-shake apparatus

ABSTRACT

An anti-shake apparatus for image stabilizing comprises an angular velocity sensor and a controller. The angular velocity sensor detects an angular velocity. The controller controls the angular velocity sensor and performs an anti-shake operation on the basis of an output signal from the angular velocity sensor. The controller performs a modification of an offset output in the value of the output signal during a predetermined period of the anti-shake operation, and does not perform the modification except for during the predetermined period.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an anti-shake apparatus for aphotographing apparatus, and in particular to the modification of theoffset output in an output signal from the angular velocity sensor in apredetermined period of the anti-shake operation.

2. Description of the Related Art

An anti-shake apparatus for a photographing apparatus is proposed. Theanti-shake apparatus corrects for hand-shake effect by moving ahand-shake correcting lens or an imaging device on a plane that isperpendicular to the optical axis, in a manner corresponding to theamount of hand-shake which occurs during the imaging process.

Japanese unexamined patent publication (KOKAI) No. H09-51465 disclosesan anti-shake apparatus that detects the electric power of the powersupply and reduces an offset output that is included in the outputsignal from the angular velocity sensor when a change in the electricpower occurs, by changing the characteristic of the filter that filtersthe output signal from the output signal of the angular velocity sensor(the gyro sensor), based on the result of a detection of the change ofthe electric power.

However, it is necessary to comprise a detection apparatus that detectsthe electric power of the power supply, besides the angular velocitysensor, so the construction of the anti-shake apparatus becomescomplicated.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide ananti-shake apparatus (an image stabilizing apparatus) that correctlydetects the hand-shake quantity in a predetermined period of theanti-shake operation without complicating the construction of theanti-shake apparatus.

According to the present invention, an anti-shake apparatus for imagestabilizing comprises an angular velocity sensor and a controller. Theangular velocity sensor detects an angular velocity. The controllercontrols the angular velocity sensor and performs an anti-shakeoperation on the basis of an output signal from the angular velocitysensor. The controller performs a modification of an offset output inthe value of the output signal during a predetermined period of theanti-shake operation, and does not perform the modification except forduring the predetermined period.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the present invention will be betterunderstood from the following description, with reference to theaccompanying drawings in which:

FIG. 1 is a perspective rear view of the embodiment of the photographingapparatus viewed from the back side;

FIG. 2 is a front view of the photographing apparatus;

FIG. 3 is a circuit construction diagram of the photographing apparatus;

FIG. 4 is a flowchart that shows the main operation of the photographingapparatus;

FIG. 5 is a flowchart that shows the detail of the interruption processof the timer;

FIG. 6 is a figure that shows calculations in the anti-shake operation;and

FIG. 7 is a flowchart that shows the detail of the drift interpolationprocessing operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is described below with reference to theembodiment shown in the drawings. In the embodiment, the photographingapparatus 1 is a digital camera. A camera lens 67 of the photographingapparatus 1 has an optical axis LX.

In order to explain the direction in the embodiment, a first directionx, a second direction y, and a third direction z are defined (see FIG.1). The first direction x is a direction which is perpendicular to theoptical axis LX. The second direction y is a direction which isperpendicular to the optical axis LX and the first direction x. Thethird direction z is a direction which is parallel to the optical axisLX and perpendicular to both the first direction x and the seconddirection y.

The imaging part of the photographing apparatus 1 comprises a PON button11, a PON switch 11 a, a photometric switch 12 a, a release button 13, arelease switch 13 a, an anti-shake button 14, an anti-shake switch 14 a,an indicating unit 17 such as an LCD monitor etc., amirror-aperture-shutter unit 18, a DSP 19, a CPU 21, an AE (automaticexposure) unit 23, an AF (automatic focus) unit 24, an imaging unit 39 ain the anti-shake unit 30, and a camera lens 67 (see FIGS. 1, 2, and 3).

Whether the PON switch 11 a is in the ON state or the OFF state, isdetermined by the state of the PON button 11, so that the ON/OFF statesof the photographing apparatus 1 correspond to the ON/OFF states of thePON switch 11 a.

The photographic subject image is captured as an optical image throughthe camera lens 67 by the imaging unit 39 a, and the captured image isdisplayed on the indicating unit 17. The photographic subject image canbe optically observed by the optical finder (not depicted).

When the release button 13 is partially depressed by the operator, thephotometric switch 12 a changes to the ON state so that the photometricoperation, the AF sensing operation, and the focusing operation areperformed.

When the release button 13 is fully depressed by the operator, therelease switch 13 a changes to the ON state so that the imagingoperation by the imaging unit 39 a (the imaging apparatus) is performed,and the image, which is captured, is stored.

In the embodiment, the anti-shake operation is performed from the pointwhen the release switch 13 a is set to the ON state, to the point whenthe release sequence operation (the photographing operation) isfinished. However, the anti-shake operation may be performed except forduring the release sequence operation.

The mirror-aperture-shutter unit 18 is connected to port P7 of the CPU21 and performs an UP/DOWN operation of a mirror 18 a (a mirror-upoperation and a mirror-down operation), an OPEN/CLOSE operation of theaperture, and an OPEN/CLOSE operation of a shutter 18 b corresponding tothe ON state of the release switch 13 a.

While the mirror-up operation of the mirror 18 a is being performed, orwhile the mirror up switch (not depicted) is set to the ON state so thatthe movement of the front curtain of the shutter 18 b is beingperformed, a front curtain movement signal (not depicted) is set to theON state.

The DSP 19 is connected to port P9 of the CPU 21, and it is connected tothe imaging unit 39 a. Based on a command from the CPU 21, the DSP 19performs the calculation operations, such as the image processingoperation etc., on the image signal obtained by the imaging operation ofthe imaging unit 39 a.

The CPU 21 is a control apparatus that controls each part of thephotographing apparatus 1 regarding the imaging operation and theanti-shake operation (i.e. the image stabilizing operation). Theanti-shake operation includes both the movement of the movable unit 30 aand position-detection efforts.

Further, the CPU 21 stores a value of the anti-shake parameter IS thatdetermines whether the photographing apparatus 1 is in the anti-shakemode or not, a value of a release time counter RLST, and a value of arelease state parameter RP.

The value of the release state parameter RP changes with respect to therelease sequence operation. When the release sequence operation isperformed, the value of the release state parameter RP is set to 1 (seesteps S21 to S30 in FIG. 4), and when the release sequence operation isfinished, the value of the release state parameter RP is set (reset) to0 (see steps S13 and S30 in FIG. 4).

The release time counter RLST is a time counter of an elapsed time fromthe point when the release sequence operation commences, which functionsby increasing the value of the release time counter RLST by 1, withevery interruption process that occurs at a predetermined time intervalof 1 ms, under a predetermined condition (see step S73 in FIG. 7).

The CPU 21 performs the release sequence operation after the releaseswitch 13 a is set to the ON state.

Further, the CPU 21 stores values of a first before-drift-interpolationdigital angular velocity signal BVx_(n), a secondbefore-drift-interpolation digital angular velocity signal BVy_(n), afirst digital angular velocity signal Vx_(n), a second digital angularvelocity signal Vy_(n), a first digital angular velocity VVx_(n), asecond digital angular velocity VVy_(n), a digital displacement angleBx_(n), a second digital displacement angle By_(n), a coordinate ofposition S_(n) in the first direction x: Sx_(n), a coordinate ofposition S_(n) in the second direction y: Sy_(n), a first driving forceDx_(n), a second driving force Dy_(n), a coordinate of position P_(n)after A/D conversion in the first direction x: pdx_(n), a coordinate ofposition P_(n) after A/D conversion in the second direction y: pdy_(n),a first subtraction value ex_(n), a second subtraction value ey_(n), afirst proportional coefficient Kx, a second proportional coefficient Ky,a sampling cycle θ of the anti-shake operation, a first integralcoefficient Tix, a second integral coefficient Tiy, a first differentialcoefficient Tdx, and a second differential coefficient Tdy.

In the embodiment, the first digital angular velocity signal Vx_(n) iscalculated by performing the drift interpolation processing operation onthe first before-drift-interpolation digital angular velocity signalBVx_(n) that is based on the first angular velocity vx.

Similarly, the second digital angular velocity signal Vy_(n) iscalculated by performing the drift interpolation processing operation onthe second before-drift-interpolation digital angular velocity signalBVy_(n) that is based on the second angular velocity vy.

In the drift interpolation processing operation, the offset outputcorresponding to the large change of electric power based on releaseoperations such as the mirror-up operation of the mirror 18 a, etc.,that occur in a predetermined period (a drift-interpolation referencetime GTC: a first time) after the release sequence operation commences(after the release switch 13 a is set to the ON state), is interpolated;in other words, the offset component of the output from the angularvelocity detection unit 25 is reduced. Or, the values of the first andsecond before-drift-interpolation digital angular velocity signalsBVx_(n) and BVy_(n) are reduced, so the values of the first and seconddigital angular velocity signals Vx_(n) and Vy_(n) are respectivelyreduced as the offset components from the values of the first and secondbefore-drift-interpolation digital angular velocity signals BVx_(n) andBVy_(n).

When the value of the release time counter RLST is less than or equal tothe value of the drift-interpolation reference time GTC, the driftinterpolation processing operation is performed.

The value of the drift-interpolation reference time GTC is set as doublethe time constant of the first and second high-pass filter circuits 27 aand 27 b, and is stored in the CPU 21.

When the release sequence operation commences, the large change in theelectric power of the main power supply of the photographing apparatus 1affects the high impedance part of the gyro signal processing circuit,such as the first high-pass filter circuit 27 a etc., so that an offset(a lag from the reference value) occurs in the output from the angularvelocity detection unit 25 (the offset output occurs).

In the calculation of the hand-shake quantity and the position to wherethe movable unit 30 a should be moved for anti-shake operation, theoutput signal from the angular velocity detection unit 25 is integrated;therefore, the change of the value of the output signal caused by theoffset output causes a drift in the movement of the movable unit 30 aduring the anti-shake operation. This unnecessary movement means thatthe anti-shake operation cannot be performed correctly due to the drift.

The offset output indicates a maximum offset output value OF immediatelyafter the release sequence operation commences, and subsequently theoffset output gradually decreases, taking the duration of thedrift-interpolation reference time GTC, which is double the timeconstant of the first and second high-pass filter circuits 27 a and 27b.

The inclination of the decrease of the offset output during thedrift-interpolation reference time GTC is actually nonlinear; however,it can be considered as linear in the drift interpolation processingoperation.

In the embodiment, the drift interpolation processing operation isperformed during a predetermined period (the drift-interpolationreference time GTC), after the release sequence operation commences. Inthe drift interpolation processing operation, the offset components ofthe output from the angular velocity detection unit 25 (first and secondbefore-gain digital angular velocity signals BVx_(n) and BVy_(n), seestep S52 in FIG. 5) are reduced (modified) as the decrease of the offsetoutput, corresponding to the elapsed time from when the release sequenceoperation commences, is almost linear. Therefore, the anti-shakeoperation (the detection of the hand-shake quantity) can be performedcorrectly, even if an offset from the angular velocity detection unit 25occurs.

The maximum offset output value OF is calculated in an adjustmentprocess of the production and is stored in the CPU 21.

The AE unit (an exposure calculating unit) 23 performs the photometricoperation and calculates the photometric values, based on the subjectbeing photographed. The AE unit 23 also calculates the aperture valueand the time length of the exposure, with respect to the photometricvalues, both of which are needed for imaging. The AF unit 24 performsthe AF sensing operation and the corresponding focusing operation, bothof which are needed for imaging. In the focusing operation, the cameralens 67 is re-positioned along the optical axis in the LX direction.

The anti-shake part (the anti-shake apparatus) of the photographingapparatus 1 comprises an anti-shake button 14, an anti-shake switch 14a, an indicating unit 17, a CPU 21, an angular velocity detection unit25, a driver circuit 29, an anti-shake unit 30, a hall-elementsignal-processing unit 45 (a magnetic-field change-detecting element),and the camera lens 67.

When the anti-shake button 14 is depressed by the operator, theanti-shake switch 14 a is changed to the ON state so that the anti-shakeoperation, in which the angular velocity detection unit 25 and theanti-shake unit 30 are driven independently of the other operationswhich include the photometric operation etc., is carried out at thepredetermined time interval. When the anti-shake switch 14 a is in theON state, in other words in the anti-shake mode, the anti-shakeparameter IS is set to 1 (IS=1). When the anti-shake switch 14 a is notin the ON state, in other words in the non-anti-shake mode, theanti-shake parameter IS is set to 0 (IS=0). In the embodiment, the valueof the predetermined time interval is set to 1 ms.

The various output commands corresponding to the input signals of theseswitches are controlled by the CPU 21.

The information regarding whether the photometric switch 12 a is in theON state or OFF state is input to port P12 of the CPU 21 as a 1-bitdigital signal. The information regarding whether the release switch 13a is in the ON state or OFF state is input to port P13 of the CPU 21 asa 1-bit digital signal. The information regarding whether the anti-shakeswitch 14 a is in the ON state or OFF state is input to port P14 of theCPU 21 as a 1-bit digital signal.

The AE unit 23 is connected to port P4 of the CPU 21 for inputting andoutputting signals. The AF unit 24 is connected to port P5 of the CPU 21for inputting and outputting signals. The indicating unit 17 isconnected to port P6 of the CPU 21 for inputting and outputting signals.

Next, the details of the input and output relationships between the CPU21 and the angular velocity detection unit 25, the driver circuit 29,the anti-shake unit 30, and the hall-element signal-processing unit 45are explained.

The angular velocity detection unit 25 has a first angular velocitysensor 26 a, a second angular velocity sensor 26 b, a first high-passfilter circuit 27 a, a second high-pass filter circuit 27 b, a firstamplifier 28 a and a second amplifier 28 b.

The first angular velocity sensor 26 a detects the angular velocity of arotary motion (the yawing) of the photographing apparatus 1 about theaxis of the second direction y (the velocity-component in the firstdirection x of the angular velocity of the photographing apparatus 1).The first angular velocity sensor 26 a is a gyro sensor that detects ayawing angular velocity.

The second angular velocity sensor 26 b detects the angular velocity ofa rotary motion (the pitching) of the photographing apparatus 1 aboutthe axis of the first direction x (detects the velocity-component in thesecond direction y of the angular velocity of the photographingapparatus 1). The second angular velocity sensor 26 b is a gyro sensorthat detects a pitching angular velocity.

The first high-pass filter circuit 27 a reduces a low frequencycomponent of the signal output from the first angular velocity sensor 26a, because the low frequency component of the signal output from thefirst angular velocity sensor 26 a includes signal elements that arebased on a null voltage and a panning-motion, neither of which arerelated to hand-shake.

The second high-pass filter circuit 27 b reduces a low frequencycomponent of the signal output from the second angular velocity sensor26 b, because the low frequency component of the signal output from thesecond angular velocity sensor 26 b includes signal elements that arebased on a null voltage and a panning-motion, neither of which arerelated to hand-shake.

The first amplifier 28 a amplifies a signal regarding the yawing angularvelocity, whose low frequency component has been reduced, and outputsthe analog signal to the A/D converter A/D 0 of the CPU 21 as a firstangular velocity vx.

The second amplifier 28 b amplifies a signal regarding the pitchingangular velocity, whose low frequency component has been reduced, andoutputs the analog signal to the A/D converter A/D 1 of the CPU 21 as asecond angular velocity vy.

The reduction of the low frequency signal component is a two-stepprocess; the primary part of the analog high-pass filter processingoperation is performed first by the first and second high-pass filtercircuits 27 a and 27 b, followed by the secondary part of the digitalhigh-pass filter processing operation that is performed by the CPU 21.

The cut off frequency of the secondary part of the digital high-passfilter processing operation is higher than that of the primary part ofthe analog high-pass filter processing operation.

In the digital high-pass filter processing operation, the value of atime constant (a first high-pass filter time constant hx and a secondhigh-pass filter time constant hy) can be easily changed.

The supply of electric power to the CPU 21 and each part of the angularvelocity detection unit 25 begins after the PON switch 11 a is set tothe ON state (the main power supply is set to the ON state). Thecalculation of a hand-shake quantity begins after the PON switch 11 a isset to the ON state.

The CPU 21 converts the first angular velocity vx, which is input to theA/D converter A/D 0, to a first before-drift-interpolation digitalangular velocity signal BVx_(n) (A/D conversion operation); calculates afirst digital angular velocity signal Vx_(n) (the drift interpolationprocessing operation corresponding to the offset output during therelease sequence operation); calculates a first digital angular velocityVVx_(n) by reducing a low frequency component of the first digitalangular velocity signal Vx_(n) (the digital high-pass filter processingoperation) because the low frequency component of the first digitalangular velocity signal Vx_(n) includes signal elements that are basedon a null voltage and a panning-motion, neither of which are related tohand-shake; and calculates a hand shake quantity (a hand shakedisplacement angle: a first digital displacement angle Bx_(n)) byintegrating the first digital angular velocity VVx_(n) (the integrationprocessing operation).

Similarly the CPU 21 converts the second angular velocity vy, which isinput to the A/D converter A/D 1, to a second before-drift-interpolationdigital angular velocity signal BVy_(n) (A/D conversion operation);calculates a second digital angular velocity signal Vy_(n) (the driftinterpolation processing operation corresponding to the offset outputduring the release sequence operation); calculates a second digitalangular velocity VVy_(n) by reducing a low frequency component of thesecond digital angular velocity signal Vy_(n) (the digital high-passfilter processing operation) because the low frequency component of thesecond digital angular velocity signal Vy_(n) includes signal elementsthat are based on a null voltage and a panning-motion, neither of whichare related to hand-shake; and calculates a hand shake quantity (a handshake displacement angle: a second digital displacement angle By_(n)) byintegrating the second digital angular velocity VVy_(n) (the integrationprocessing operation).

Accordingly, the CPU 21 and the angular velocity detection unit 25 use afunction to calculate the hand-shake quantity.

The value “n” is an integer that is greater than 1, and indicates alength of time (ms) from the point when the interruption process of thetimer commences, (t=1, and see step S12 in FIG. 4) to the point when thelatest anti-shake operation is performed (t=n).

The drift interpolation processing operation regarding the firstdirection x that is a calculation of the first digital angular velocitysignal Vx_(n) (see “interpolation” of (1) in FIG. 6), is performed by acalculation based on the first before-drift-interpolation digitalangular velocity signal BVx_(n), the drift-interpolation reference timeGTC, the maximum offset output value OF, and the release time counterRLST (Vx_(n)=BVx_(n)−(OF−OF×RLST÷GTC), see step S72 in FIG. 7).

Similarly, the drift interpolation processing operation regarding thesecond direction y that is a calculation for the second digital angularvelocity signal Vy_(n), is performed by a calculation based on thesecond before-drift-interpolation digital angular velocity signalBVy_(n), the drift-interpolation reference time GTC, the maximum offsetoutput value OF, and the release time counter RLST(Vy_(n)=BVy_(n)−(OF−OF×RLST÷GTC)).

The drift-interpolation processing operation is not performed except forduring the predetermined period (the drift-interpolation reference timeGTC), after the release sequence operation commences.

In the digital high-pass filter processing operation regarding the firstdirection x, the first digital angular velocity VVx_(n) is calculated bydividing the summation of the first digital angular velocity VVx₁ toVVx_(n-1) calculated by the interruption process of the timer before the1 ms predetermined time interval (before the latest anti-shake operationis performed), by the first high-pass filter time constant hx, and thensubtracting the resulting quotient from the first digital angularvelocity signal Vx_(n)(VVx_(n)=Vx_(n)−(ΣVVx_(n-1))÷hx, see (1) in FIG.6).

In the digital high-pass filter processing operation regarding thesecond direction y, the second digital angular velocity VVy_(n) iscalculated by dividing the summation of the second digital angularvelocity VVy₁ to VVy_(n-1) calculated by the interruption process of thetimer before the 1 ms predetermined time interval (before the latestanti-shake operation is performed), by the second high-pass filter timeconstant hy, and then subtracting the resulting quotient from the seconddigital angular velocity signal Vy_(n)(VVy_(n)=Vy_(n)−(ΣVVy_(n-1))÷hy).

In the embodiment, the angular velocity detection operation in (portionof) the interruption process of the timer includes a process in theangular velocity detection unit 25 and a process of inputting process ofthe first and second angular velocities vx and vy from the angularvelocity detection unit 25 to the CPU 21.

In the integration processing operation regarding the first direction x,the first digital displacement angle Bx_(n) is calculated by thesummation from the first digital angular velocity VVx₁ at the point whenthe interruption process of the timer commences, t=1, (see step S12 inFIG. 4) to the first digital angular velocity VVx_(n) at the point whenthe latest anti-shake operation is performed (t=n), (Bx_(n)=ΣVVx_(n),see (3) in FIG. 6).

Similarly, in the integration processing operation regarding the seconddirection y, the second digital displacement angle By_(n) is calculatedby the summation from the second digital angular velocity VVy₁ at thepoint when the interruption process of the timer commences to the seconddigital angular velocity VVy_(n) at the point when the latest anti-shakeoperation is performed (By_(n)=ΣVVy_(n)).

The CPU 21 calculates the position S_(n) where the imaging unit 39 a(the movable unit 30 a) should be moved, corresponding to the hand-shakequantity (the first and second digital displacement angles Bx_(n) andBy_(n)) calculated for the first direction x and the second direction y,based on a position conversion coefficient zz (a first positionconversion coefficient zx for the first direction x and a secondposition conversion coefficient zy for the second direction y).

The coordinate of position S_(n) in the first direction x is defined asSx_(n), and the coordinate of position S_(n) in the second direction yis defined as Sy_(n). The movement of the movable unit 30 a, whichincludes the imaging unit 39 a, is performed by using electro-magneticforce and is described later.

The driving force D_(n) drives the driver circuit 29 in order to movethe movable unit 30 a to the position S_(n). The coordinate of thedriving force D_(n) in the first direction x is defined as the firstdriving force Dx_(n) (after D/A conversion: a first PWM duty dx). Thecoordinate of the driving force D_(n) in the second direction y isdefined as the second driving force Dy_(n) (after D/A conversion: asecond PWM duty dy).

In a positioning operation regarding the first direction x, thecoordinate of position S_(n) in the first direction x is defined asSx_(n), and is the product of the latest first digital displacementangle Bx_(n) and the first position conversion coefficient zx(Sx_(n)=zx×Bx_(n), see (3) in FIG. 6).

In a positioning operation regarding the second direction y, thecoordinate of position S_(n) in the second direction y is defined asSy_(n), and is the product of the latest second digital displacementangle By_(n) and the second position conversion coefficient zy(Sy_(n)=zy×By_(n)).

The anti-shake unit 30 is an apparatus that corrects for the hand-shakeeffect by moving the imaging unit 39 a to the position S_(n), bycanceling the lag of the photographing subject image on the imagingsurface of the imaging device of the imaging unit 39 a, and bystabilizing the photographing subject image displayed on the imagingsurface of the imaging device, during the exposure time and when theanti-shake operation is performed (IS=1).

The anti-shake unit 30 has a fixed unit 30 b, and a movable unit 30 awhich includes the imaging unit 39 a and can be moved about on the xyplane.

During the exposure time when the anti-shake operation is not performed(IS=0), the movable unit 30 a is fixed to (held at) a predeterminedposition. In the embodiment, the predetermined position is at the centerof the range of movement.

The anti-shake unit 30 does not have a fixed-positioning mechanism thatmaintains the movable unit 30 a in a fixed position when the movableunit 30 a is not being driven (drive OFF state).

The driving of the movable unit 30 a of the anti-shake unit 30,including movement to a predetermined fixed (held) position, isperformed by the electro-magnetic force of the coil unit for driving andthe magnetic unit for driving, through the driver circuit 29 which hasthe first PWM duty dx input from the PWM 0 of the CPU 21 and has thesecond PWM duty dy input from the PWM 1 of the CPU 21 (see (5) in FIG.6).

The detected-position P_(n) of the movable unit 30 a, either before orafter the movement effected by the driver circuit 29, is detected by thehall element unit 44 a and the hall-element signal-processing unit 45.

Information regarding the first coordinate of the detected-positionP_(n) in the first direction x, in other words a first detected-positionsignal px, is input to the A/D converter A/D 2 of the CPU 21 (see (2) inFIG. 6). The first detected-position signal px is an analog signal thatis converted to a digital signal by the A/D converter A/D 2 (A/Dconversion operation). The first coordinate of the detected-positionP_(n) in the first direction x, after the A/D conversion operation, isdefined as pdx_(n) and corresponds to the first detected-position signalpx.

Information regarding the second coordinate of the detected-positionP_(n) in the second direction y, in other words a seconddetected-position signal py, is input to the A/D converter A/D 3 of theCPU 21. The second detected-position signal py is an analog signal thatis converted to a digital signal by the A/D converter A/D 3 (A/Dconversion operation). The second coordinate of the detected-positionP_(n) in the second direction y, after the A/D conversion operation, isdefined as pdy_(n) and corresponds to the second detected-positionsignal py.

The PID (Proportional Integral Differential) control calculates thefirst and second driving forces Dx_(n) and Dy_(n) on the basis of thecoordinate data for the detected-position P_(n) (pdx_(n), pdy_(n)) andthe position S_(n) (Sx_(n), Sy_(n)) following movement.

The calculation of the first driving force Dx_(n) is based on the firstsubtraction value ex_(n), the first proportional coefficient Kx, thesampling cycle θ, the first integral coefficient Tix, and the firstdifferential coefficient Tdx(Dx_(n)=Kx×{ex_(n)θ÷Tix×Σex_(n)+Tdx÷θ×(ex_(n)−ex_(n-1))}, see (4) inFIG. 6). The first subtraction value ex_(n) is calculated by subtractingthe first coordinate of the detected-position P_(n) in the firstdirection x after the A/D conversion operation, pdx_(n), from thecoordinate of position S_(n) in the first direction x,Sx_(n)(ex_(n)=Sx_(n)-pdx_(n)).

The calculation of the second driving force Dy_(n) is based on thesecond subtraction value ey_(n), the second proportional coefficient Ky,the sampling cycle θ, the second integral coefficient Tiy, and thesecond differential coefficient Tdy(D_(n)=Ky×{ey_(n)+θ÷Tiy×Σey_(n)+Tdy÷θ×(ey_(n)−ey_(n-1))}). The secondsubtraction value ey_(n) is calculated by subtracting the secondcoordinate of the detected-position P_(n) in the second direction yafter the A/D conversion operation, pdy_(n), from the coordinate ofposition S_(n) in the second direction y, Sy_(n)(ey_(n)=Sy_(n)−pdy_(n)).

The value of the sampling cycle θ is set to a predetermined timeinterval of 1 ms.

Driving the movable unit 30 a to the position S_(n), (Sx_(n), Sy_(n))corresponding to the anti-shake operation of the PID control, isperformed when the photographing apparatus 1 is in the anti-shake mode(IS=1) where the anti-shake switch 14 a is set to the ON state.

When the anti-shake parameter IS is 0, the PID control that does notcorrespond to the anti-shake operation is performed so that the movableunit 30 a is moved to the center of the range of movement (thepredetermined position).

The movable unit 30 a has a coil unit for driving that is comprised of afirst driving coil 31 a and a second driving coil 32 a, an imaging unit39 a that has the imaging device, and a hall element unit 44 a as amagnetic-field change-detecting element unit. In the embodiment, theimaging device is a CCD; however, the imaging device may be anotherimaging device such as a CMOS etc.

The fixed unit 30 b has a magnetic unit for driving that is comprised ofa first position-detecting and driving magnet 411 b, a secondposition-detecting and driving magnet 412 b, a first position-detectingand driving yoke 431 b, and a second position-detecting and driving yoke432 b.

The fixed unit 30 b movably supports the movable unit 30 a in the firstdirection x and in the second direction y.

When the center area of the imaging device is intersected by the opticalaxis LX of the camera lens 67, the relationship between the position ofthe movable unit 30 a and the position of the fixed unit 30 b isarranged so that the movable unit 30 a is positioned at the center ofits range of movement in both the first direction x and the seconddirection y, in order to utilize the full size of the imaging range ofthe imaging device.

A rectangle shape, which is the form of the imaging surface of theimaging device, has two diagonal lines. In the embodiment, the center ofthe imaging device is at the intersection of these two diagonal lines.

The first driving coil 31 a, the second driving coil 32 a, and the hallelement unit 44 a are attached to the movable unit 30 a.

The first driving coil 31 a forms a seat and a spiral shaped coilpattern. The coil pattern of the first driving coil 31 a has lines whichare parallel to the second direction y, thus creating the firstelectro-magnetic force to move the movable unit 30 a that includes thefirst driving coil 31 a, in the first direction x.

The first electro-magnetic force occurs on the basis of the currentdirection of the first driving coil 31 a and the magnetic-fielddirection of the first position-detecting and driving magnet 411 b.

The second driving coil 32 a forms a seat and a spiral shaped coilpattern. The coil pattern of the second driving coil 32 a has lineswhich are parallel to the first direction x, thus creating the secondelectro-magnetic force to move the movable unit 30 a that includes thesecond driving coil 32 a, in the second direction y.

The second electro-magnetic force occurs on the basis of the currentdirection of the second driving coil 32 a and the magnetic-fielddirection of the second position-detecting and driving magnet 412 b.

The first and second driving coils 31 a and 32 a are connected to thedriver circuit 29, which drives the first and second driving coils 31 aand 32 a, through the flexible circuit board (not depicted). The firstPWM duty dx is input to the driver circuit 29 from the PWM 0 of the CPU21, and the second PWM duty dy is input to the driver circuit 29 fromthe PWM 1 of the CPU 21. The driver circuit 29 supplies power to thefirst driving coil 31 a that corresponds to the value of the first PWMduty dx, and to the second driving coil 32 a that corresponds to thevalue of the second PWM duty dy, to drive the movable unit 30 a.

The first position-detecting and driving magnet 411 b is attached to themovable unit side of the fixed unit 30 b, where the firstposition-detecting and driving magnet 411 b faces the first driving coil31 a and the horizontal hall element hh10 in the third direction z.

The second position-detecting and driving magnet 412 b is attached tothe movable unit side of the fixed unit 30 b, where the secondposition-detecting and driving magnet 412 b faces the second drivingcoil 32 a and the vertical hall element hv10 in the third direction z.

The first position-detecting and driving magnet 411 b is attached to thefirst position-detecting and driving yoke 431 b, under the conditionwhere the N pole and S pole are arranged in the first direction x. Thefirst position-detecting and driving yoke 431 b is attached to the fixedunit 30 b, on the side of the movable unit 30 a, in the third directionz.

The second position-detecting and driving magnet 412 b is attached tothe second position-detecting and driving yoke 432 b, under thecondition where the N pole and S pole are arranged in the seconddirection y. The second position-detecting and driving yoke 432 b isattached to the fixed unit 30 b, on the side of the movable unit 30 a,in the third direction z.

The first and second position-detecting and driving yokes 431 b, 432 bare made of a soft magnetic material.

The first position-detecting and driving yoke 431 b prevents themagnetic-field of the first position-detecting and driving magnet 411 bfrom dissipating to the surroundings, and raises the magnetic-fluxdensity between the first position-detecting and driving magnet 411 band the first driving coil 31 a, and between the firstposition-detecting and driving magnet 411 b and the horizontal hallelement hh10.

The second position-detecting and driving yoke 432 b prevents themagnetic-field of the second position-detecting and driving magnet 412 bfrom dissipating to the surroundings, and raises the magnetic-fluxdensity between the second position-detecting and driving magnet 412 band the second driving coil 32 a, and between the secondposition-detecting and driving magnet 412 b and the vertical hallelement hv10.

The hall element unit 44 a is a single-axis unit that contains twomagnetoelectric converting elements (magnetic-field change-detectingelements) utilizing the Hall Effect to detect the firstdetected-position signal px and the second detected-position signal pyspecifying the first coordinate in the first direction x and the secondcoordinate in the second direction y, respectively, of the presentposition P_(n) of the movable unit 30 a.

One of the two hall elements is a horizontal hall element hh10 fordetecting the first coordinate of the position P_(n) of the movable unit30 a in the first direction x, and the other is a vertical hall elementhv10 for detecting the second coordinate of the position P_(n) of themovable unit 30 a in the second direction y.

The horizontal hall element hh10 is attached to the movable unit 30 a,where the horizontal hall element hh10 faces the firstposition-detecting and driving magnet 411 b of the fixed unit 30 b inthe third direction z.

The vertical hall element hv10 is attached to the movable unit 30 a,where the vertical hall element hv10 faces the second position-detectingand driving magnet 412 b of the fixed unit 30 b in the third directionz.

When the center of the imaging device intersects the optical axis LX, itis desirable to have the horizontal hall element hh10 positioned on thehall element unit 44 a facing an intermediate area between the N poleand S pole of the first position-detecting and driving magnet 411 b inthe first direction x, as viewed from the third direction z. In thisposition, the horizontal hall element hh10 utilizes the maximum range inwhich an accurate position-detecting operation can be performed based onthe linear output-change (linearity) of the single-axis hall element.

Similarly, when the center of the imaging device intersects the opticalaxis LX, it is desirable to have the vertical hall element hv10positioned on the hall element unit 44 a facing an intermediate areabetween the N pole and S pole of the second position-detecting anddriving magnet 412 b in the second direction y, as viewed from the thirddirection z.

The hall-element signal-processing unit 45 has a first hall-elementsignal-processing circuit 450 and a second hall-elementsignal-processing circuit 460.

The first hall-element signal-processing circuit 450 detects ahorizontal potential-difference x10 between the output terminals of thehorizontal hall element hh10 that is based on an output signal of thehorizontal hall element hh10.

The first hall-element signal-processing circuit 450 outputs the firstdetected-position signal px, which specifies the first coordinate of theposition P_(n) of the movable unit 30 a in the first direction x, to theA/D converter A/D 2 of the CPU 21, on the basis of the horizontalpotential-difference x10.

The second hall-element signal-processing circuit 460 detects a verticalpotential-difference y10 between the output terminals of the verticalhall element hv10 that is based on an output signal of the vertical hallelement hv10.

The second hall-element signal-processing circuit 460 outputs the seconddetected-position signal py, which specifies the second coordinate ofthe position P_(n) of the movable unit 30 a in the second direction y,to the A/D converter A/D 3 of the CPU 21, on the basis of the verticalpotential-difference y10.

Next, the main operation of the photographing apparatus 1 in theembodiment is explained by using the flowchart in FIG. 4.

When the photographing apparatus 1 is set to the ON state, theelectrical power is supplied to the angular velocity detection unit 25so that the angular velocity detection unit 25 is set to the ON state instep S11.

In step S12, the interruption process of the timer at the predeterminedtime interval (1 ms) commences. In step S13, the value of the releasestate parameter RP is set to 0. The detail of the interruption processof the timer in the embodiment is explained later by using the flowchartin FIG. 5.

In step S14, it is determined whether the photometric switch 12 a is setto the ON state. When it is determined that the photometric switch 12 ais not set to the ON state, the operation returns to step S14 and theprocess in step S14 is repeated. Otherwise, the operation continues onto step S15.

In step S15, it is determined whether the anti-shake switch 14 a is setto the ON state. When it is determined that the anti-shake switch 14 ais not set to the ON state, the value of the anti-shake parameter IS isset to 0 in step S16. Otherwise, the value of the anti-shake parameterIS is set to 1 in step S17.

In step S18, the AE sensor of the AE unit 23 is driven, the photometricoperation is performed, and the aperture value and exposure time arecalculated.

In step S19, the AF sensor and the lens control circuit of the AF unit24 are driven to perform the AF sensing and focus operations,respectively.

In step S20, it is determined whether the release switch 13 a is set tothe ON state. When the release switch 13 a is not set to the ON state,the operation returns to step S14 and the process in steps S14 to S19 isrepeated. Otherwise, the operation continues to step S21 and then therelease sequence operation commences.

In step S21, the value of the release state parameter RP is set to 1.

In step S22, the value of the release time counter RLST is set to 0.

In step S23, the mirror-up operation of the mirror 18 a and the apertureclosing operation corresponding to the aperture value that is eitherpreset or calculated, are performed by the mirror-aperture-shutter unit18.

After the mirror-up operation is finished, the opening operation of theshutter 18 b (the movement of the front curtain of the shutter 18 b)commences in step S24.

In step S25, the exposure operation, i.e., the electric chargeaccumulation of the imaging device (CCD etc.), is performed. After theexposure time has elapsed, the closing operation of the shutter 18 b(the movement of the rear curtain in the shutter 18 b), the mirror-downoperation of the mirror 18 a, and the opening operation of the apertureare performed by the mirror-aperture-shutter unit 18, in step S26.

In step S27, the electric charge which has accumulated in the imagingdevice during the exposure time is read. In step S28, the CPU 21communicates with the DSP 19 so that the image processing operation isperformed based on the electric charge read from the imaging device. Theimage, on which the image processing operation is performed, is storedto the memory in the photographing apparatus 1. In step S29, the imagethat is stored in the memory is displayed on the indicating unit 17. Instep S30, the value of the release state parameter RP is set to 0 sothat the release sequence operation is finished, and the operation thenreturns to step S14, in other words the photographing apparatus 1 is setto a state where the next imaging operation can be performed.

Next, the interruption process of the timer in the embodiment, whichcommences in step S12 in FIG. 4 and is performed at every predeterminedtime interval (1 ms) independent of the other operations, is explainedby using the flowchart in FIG. 5.

When the interruption process of the timer commences, the first angularvelocity vx, which is output from the angular velocity detection unit25, is input to the A/D converter A/D 0 of the CPU 21 and converted tothe first before-drift-interpolation digital angular velocity signalBVx_(n), in step S51. The second angular velocity vy, which is alsooutput from the angular velocity detection unit 25, is input to the A/Dconverter A/D 1 of the CPU 21 and converted to the secondbefore-drift-interpolation digital angular velocity signal BVy_(n) (theangular velocity detection operation).

In step S52, the drift interpolation processing operation is performed;the drift components in the first and second before-drift-interpolationdigital angular velocity signals BVx_(n) and BVy_(n) are reducedcorresponding to the offset output during the release sequenceoperation, and the first and second digital angular velocity signalsVx_(n) and Vy_(n) are calculated. However, except for during thepredetermined period (the drift-interpolation reference time GTC) afterthe release sequence operation commences, the drift interpolationprocessing operation is not performed, so the values of the first andsecond digital angular velocity signals Vx_(n) and Vy_(n) arerespectively set to the same as the values of the first and secondbefore-drift-interpolation digital angular velocity signals BVx_(n) andBVy_(n). The detail of the drift interpolation processing operation inthe embodiment is explained later by using the flowchart in FIG. 7.

The low frequencies of the first and second digital angular velocitysignals Vx_(n) and Vy_(n) are reduced in the digital high-pass filterprocessing operation (the first and second digital angular velocitiesVVx_(n) and VVy_(n)).

In step S53, it is determined whether the value of the release stateparameter RP is set to 1. When it is determined that the value of therelease state parameter RP is not set to 1, driving the movable unit 30a is set to OFF state, or the anti-shake unit 30 is set to a state wherethe driving control of the movable unit 30 a is not performed in stepS54. Otherwise, the operation proceeds directly to step S55.

In step S55, the hall element unit 44 a detects the position of themovable unit 30 a, and the first and second detected-position signals pxand py are calculated by the hall-element signal-processing unit 45. Thefirst detected-position signal px is then input to the A/D converter A/D2 of the CPU 21 and converted to a digital signal pdx_(n), whereas thesecond detected-position signal py is input to the A/D converter A/D 3of the CPU 21 and also converted to a digital signal pdy_(n), both ofwhich thus determine the present position P_(n) (pdx_(n), pdy_(n)) ofthe movable unit 30 a.

In step S56, it is determined whether the value of the anti-shakeparameter IS is 0. When it is determined that the value of theanti-shake parameter IS is 0 (IS=0), in other words when thephotographing apparatus is not in anti-shake mode, the position S_(n)(Sx_(n), Sy_(n)) where the movable unit 30 a (the imaging unit 39 a)should be moved is set at the center of the range of movement of themovable unit 30 a, in step S57. When it is determined that the value ofthe anti-shake parameter IS is not 0 (IS=1), in other words when thephotographing apparatus is in anti-shake mode, the position S_(n)(Sx_(n), Sy_(n)) where the movable unit 30 a (the imaging unit 39 a)should be moved is calculated on the basis of the first and secondangular velocities vx and vy, in step S58.

In step S59, the first driving force Dx_(n) (the first PWM duty dx) andthe second driving force Dy_(n) (the second PWM duty dy) of the drivingforce D_(n), which moves the movable unit 30 a to the position S_(n),are calculated on the basis of the position S_(n) (Sx_(n), Sy_(n)) thatwas determined in step S57, or step S58, and the present position P_(n)(pdx_(n), pdy_(n)).

In step S60, the first driving coil unit 31 a is driven by applying thefirst PWM duty dx to the driver circuit 29, and the second driving coilunit 32 a is driven by applying the second PWM duty dy to the drivercircuit 29, so that the movable unit 30 a is moved to position S_(n)(Sx_(n), Sy_(n)).

The process of steps S59 and S60 is an automatic control calculationthat is used with the PID automatic control for performing general(normal) proportional, integral, and differential calculations.

Next, the detail of the drift interpolation processing operation in stepS52 in FIG. 5 is explained by using the flowchart in FIG. 7. When thedrift interpolation processing operation commences, it is determinedwhether the value of the release time counter RLST is less than or equalto the value of the drift-interpolation reference time GTC, in step S71.

When it is determined that the value of the release time counter RLST isless than or equal to the value of the drift-interpolation referencetime GTC, the operation continues to step S72. Otherwise, the operation(the drift interpolation processing operation) is finished.

In step S72, the first digital angular velocity signal Vx_(n) iscalculated on the basis of the first before-drift-interpolation digitalangular velocity signal BVx_(n), the drift-interpolation reference timeGTC, the maximum offset output value OF, and the release time counterRLST (Vx_(n)=BVx_(n)−(OF−OF×RLST÷GTC).

Similarly, the second digital angular velocity signal Vy_(n) iscalculated on the basis of the second before-drift-interpolation digitalangular velocity signal BVy_(n), the drift-interpolation reference timeGTC, the maximum offset output value OF, and the release time counterRLST (Vy_(n)=BVy_(n)−(OF−OF×RLST÷GTC).

In step S73, the value of the release time counter RLST is increased bya value of 1, then the operation (the drift interpolation processingoperation) is finished.

In the embodiment, the drift interpolation processing operation for thedigital angular velocity signal is performed during the predeterminedperiod (the drift-interpolation reference time GTC), and after therelease sequence operation commences.

When the release sequence operation commences, the large change of theelectric power of the main power supply of the photographing apparatus 1occurs, which affects the high impedance part of the gyro signalprocessing circuit, such as the first high-pass filter circuit 27 aetc., so that the offset (the lag from the reference value) occurs inthe output from the angular velocity detection unit 25 (the offsetoutput occurs).

In the calculation for the hand-shake quantity and the position to wherethe movable unit 30 a should be moved for anti-shake operation, theoutput signal from the angular velocity detection unit 25 is integrated;therefore, the change of the value of the output signal caused by theoffset output causes a drift in the movement of the movable unit 30 a inthe anti-shake operation. This is an unnecessary movement for theanti-shake operation, so the anti-shake operation cannot be performedcorrectly due to this drift.

However, because of the drift interpolation processing operation in theembodiment, the offset output corresponding to the change of theelectric power of the main power supply of the photographing apparatus 1is reduced approximately linearly, so the anti-shake operation (thedetection of the hand-shake quantity) can be performed correctly.

Further, in the embodiment, the voltage used to detect the change ofelectric power of the main power supply of the photographing apparatus1, is not detected by using detection apparatus except for the angularvelocity sensor. Therefore, it is unnecessary to include anotherdetection apparatus that is different from the angular velocity sensor,so the anti-shake operation (the detection of the hand-shake quantity)can be performed correctly, even if the offset from the angular velocitydetection unit 25 occurs, without complicating the construction of theanti-shake apparatus.

Further, it is explained that the CPU 21 modifies (reduces) the offsetoutput in the output signal from the angular velocity sensor during thepredetermined period of first time (the drift-interpolation referencetime GTC), and after the release switch 13 a is set to the ON state (therelease sequence operation commences). However, this modification(reduction) of the offset output in the output signal from the angularvelocity sensor may be performed during another period of the anti-shakeoperation, which may be performed except for during the release sequenceoperation, when a large change of the electric power of the main powersupply of the photographing apparatus 1 occurs, such as a charge periodof the electric flash (strobe light, not depicted) of the photographingapparatus 1.

Further, it is explained that the movable unit 30 a has the imagingdevice; however, the movable unit 30 a may have a hand-shake correctinglens instead of the imaging device.

Further, it is explained that the hall element is used for positiondetection as the magnetic-field change-detecting element. However,another detection element, an MI (Magnetic Impedance) sensor such as ahigh-frequency carrier-type magnetic-field sensor, a magneticresonance-type magnetic-field detecting element, or an MR(Magneto-Resistance effect) element may be used for position detectionpurposes. When one of either the MI sensor, the magnetic resonance-typemagnetic-field detecting element, or the MR element is used, theinformation regarding the position of the movable unit can be obtainedby detecting the magnetic-field change, similar to using the hallelement.

Although the embodiment of the present invention has been describedherein with reference to the accompanying drawings, obviously manymodifications and changes may be made by those skilled in this artwithout departing from the scope of the invention.

The present disclosure relates to subject matter contained in JapanesePatent Application No. 2006-192647 (filed on Jul. 13, 2006), which isexpressly incorporated herein by reference, in its entirety.

1. An anti-shake apparatus for image stabilizing, comprising: an angularvelocity sensor that detects an angular velocity; and a controller thatcontrols said angular velocity sensor and performs an anti-shakeoperation on the basis of an output signal from said angular velocitysensor, said controller beginning performing a modification of an offsetoutput in the value of said output signal at a beginning of apredetermined period of said anti-shake operation, wherein saidpredetermined period begins when a release switch of a photographingapparatus including said anti-shake apparatus is set to an ON state andends after a first time elapses.
 2. The anti-shake apparatus accordingto claim 1, wherein a length of said first time is double a timeconstant of a circuit that performs a high-pass filter processingoperation on said output signal from said angular velocity sensor. 3.The anti-shake apparatus according to claim 1, wherein said modificationis performed as said offset output decreases linearly from acommencement of said predetermined period to a finish of saidpredetermined period.
 4. The anti-shake apparatus according to claim 1,wherein said controller does not perform said modification except forduring said predetermined period.
 5. A photographing apparatus,comprising: an angular velocity sensor that detects an angular velocity;and a controller that controls said angular velocity sensor and performsan anti-shake operation for image stabilizing on the basis of an outputsignal from said angular velocity sensor, said controller beginningperforming a modification of an offset output in the value of saidoutput signal at a beginning of a predetermined period of saidanti-shake operation of a photographing operation, wherein saidpredetermined period begins when a release switch of a photographingapparatus including said anti-shake apparatus is set to an ON state andends after a first time elapses.
 6. The anti-shake apparatus accordingto claim 1, wherein the controller performs the modification of theoffset output by subtracting the offset output from the output signal ofthe angular velocity sensor.
 7. The anti-shake apparatus according toclaim 1, wherein the controller further performs A/D conversion of theoutput signal from the angular velocity sensor before performing themodification of the offset output.
 8. The anti-shake apparatus accordingto claim 1, further comprising a high-pass filter circuit, wherein thehigh-pass filter circuit reduces a low frequency signal component froman analog signal of the output signal from the angular velocity sensorbefore performing the modification of the offset output, and thecontroller further reduces a low frequency signal component from adigital signal of the output signal from the angular velocity sensorafter performing the modification of the offset output.
 9. Theanti-shake apparatus according to claim 1, further comprising a driverthat moves an imaging unit to correct a hand-shake effect, wherein thecontroller performs the anti-shake operation by producing a drivingsignal of the driver based on the output signal from the angularvelocity sensor, from which the offset output has been reduced.
 10. Thephotographing apparatus according to claim 5, wherein a length of saidfirst time is double a time constant of a circuit that performs ahigh-pass filter processing operation on said output signal from saidangular velocity sensor.
 11. The photographing apparatus according toclaim 5, wherein said modification is performed as said offset outputdecreases linearly from a commencement of said predetermined period to afinish of said predetermined period.
 12. The photographing apparatusaccording to claim 5, wherein said controller does not perform saidmodification except for during said predetermined period.
 13. Thephotographing apparatus according to claim 5, wherein the controllerperforms the modification of the offset output by subtracting the offsetoutput from the output signal of the angular velocity sensor.
 14. Thephotographing apparatus according to claim 5, wherein the controllerfurther performs A/D conversion of the output signal from the angularvelocity sensor before performing the modification of the offset output.15. The photographing apparatus according to claim 5, further comprisinga high-pass filter circuit, wherein the high-pass filter circuit reducesa low frequency signal component from an analog signal of the outputsignal from the angular velocity sensor before performing themodification of the offset output, and the controller further reduces alow frequency signal component from a digital signal of the outputsignal from the angular velocity sensor after performing themodification of the offset output.
 16. The photographing apparatusaccording to claim 5, further comprising a driver that moves an imagingunit to correct a hand-shake effect, wherein the controller performs theanti-shake operation by producing a driving signal of the driver basedon the output signal from the angular velocity sensor, from which theoffset output has been reduced.